S7 Reader Documentation

Version: 4.0.0

Retrieved: 2025-10-09 15:16:15

S7 Reader

Used for reading values from Siemens S7 PLC´s. The module will read values from the PLC on when a message arrives and pass the result (Array) to the next module(s) in the flow.

Compatible with S7-200, S7-300, S7-400, S7-1200, S7-1500

Note

To read data from S7-1200 and S7-1500 PLC´s the following settings must be used on the PLC

• "Optimized block access" must be disabled for the DBs you want to access
• "Permit access with PUT/GET" must be enabled

Settings

Resource Format

Example of the resource file format.

{
   "name": "Conveyor belt controller",
   "tags": [
	   {
		   "id": "tag1",
		   "name": "ValveTemp",
		   "s7DataArea": "Input",
		   "s7DbAddress": 0,
		   "s7StartAddress": 0,
		   "s7Type": "Int",
		   "customProperty": "Metadata for tag1"
		},
		{
		   "id": "tag2",
		   "name": "ValveOpen",
		   "s7DataArea": "Input",
		   "s7DbAddress": 0,
		   "s7StartAddress": 2,
		   "s7BitAddress": 5,
		   "s7Type": "Bool",
		},
		{
		   "id": "tag3",
		   "name": "Name",
		   "s7DataArea": "DataBlock",
		   "s7DbAddress": 1,
		   "s7StartAddress": 20,
		   "s7Type": "String",
		   "length": 25,
	   },
   ]
}

The data types for the properties on the tag object are:

In addition, any number of extra fields can be added for each tag. Those fields are then added to the output messages. Use this to add additional metadata associated with each tag (see customProperty in resource example above).

Input

Any message can be used to trigger a read operation from the PLC.

Output

The result (Array) will be written to the Target Property

"targetProperty": [
    {
        "id": "tag1",
        "value": 1235,
        "name": "ValveTemp"
    },
    {
        "id": "tag2",
        "value": true,
        "name": "ValveOpen"
    },
    {
        "id": "tag3",
        "value": "Factory101",
        "name": "Name"
    }
],
"crosser":{
	"success": true
}